Machine and method to produce fiberboard tubes of polygonal cross-section

ABSTRACT

Machine and method to manufacture fiberboard tubes of polygonal cross-section for use, for instance, as air conditioning piping, forms for molding concrete columns and containers for oil, food and the like. The machine comprises a horizontally disposed tubular former. A first strip of fiberboard of a width equal to substantially the perimeter of the finished product, is scored and fed longitudinally over the tubular former while being bent applied against the faces of the tubular former. Then a second strip of fiberboard is covered with glue, then applied over the first strip along the joint of the latter, then bent, pressed and adhered to the remaining faces of the bent first strip, whereby the resulting product consists of a continuous tube made of two fiberboard layers with the joints on these layers at opposite sides of the tube. Obviously, the elements of the machine may be repeated to form fiberboard tubes of more than two layers. Preferably, means are provided to fill the joint of the first layer to make the joint leak-proof.

United States Patent Vassalos 1 Sept. 30, 1975 211 App]. No]: 140,357

us. Cl. 93/82; 93/94 PS 1m. cu B 31F 1/00 Field of Search 93/94 PS, 82, 77, 94 R References Cited UNITED STATES PATENTS l/l89l Denney M 93/82 9/1941 Haycock 93/82 Primary E.\'cmiinerDonald R. Schran [57] ABSTRACT Machine and method to manufacture fiberboard tubes of polygonal cross-section for use, for instance, as air conditioning piping, forms for molding concrete columns and containers for oil, food and the like.

The machine comprises a horizontally disposed tubular former. A first strip of fiberboard of a width equal to substantially the perimeter of the finished product, is scored and fed longitudinally over the tubular former while being bent applied against the faces of the tubular former. Then a second strip of fiberboard is covered with glue, then applied over the first strip along the joint of the latter, then bent pressed and adhered to the remaining faces of the bent first strip, whereby the resulting product consists of a continuous tube made of two fiberboard layers with the joints on these layers at opposite sides of the tube. Obviously, the elements of the machine may be repeated to form fiberboard tubes of more than two layers. Preferably, means are provided to fill the joint of the first layer to make the joint leak-proof.

3 Claims, 5 Drawing Figures U.S. Patent Sept. 30,1975 Sheet 1 of4 3,908,526

US. Patent Sept. 30,1975 Sheet 2 of4 3,908,526

MACHINE AND METHOD TO PRODUCE FIBERBOARD TUBES OF POLYGONAL CROSS-SECTION The present invention relates to a method and to a machine for making fiberboard tubes of polygonal cross-section, composed of at least two layers of fiberboard.

The general object of the present invention resides in the provision of a method and machine of the character described, which enables to produce fiberboard tubular products in continuous and automatic manner with a minimum of handling and at a fast rate, and which enables to obtain a strong and leak-proof product with the joints of the fiberboard layers out of register.

The foregoing and other objects of the invention will become more apparent during the following disclosure and by referring to the drawings, in which:

FIG. 1 is a top plan view of the machine;

FIG. 2 is a side elevation of the same; and

FIGS. 3, 4, and are cross-sections along line 33, 4-4, and 55 respectively of FIG. 2.

In the drawings, like reference characters indicate like elements throughout.

The machine comprises a horizontally disposed tubular former 1, of square cross-section, and open at its ends and defining smooth outer surfaces with no taper in the former. The latter is preferably made of steel. It has the exact shape of the inner cross-sectional area of the tubular product to be formed. If the product has a rectangular or outer polygonal cross-section, the former 1 will be modified accordingly.

The upstream end of the former l is mounted on a stationary base 2, to which is also secured a support 3 carrying at its outer end several arms 4, which are upwardly inclined and carry at their outer end four pairs of co-acting rollers 5 and 6, the top rollers 5 being scoring rollers for cardboard. The nip of the rollers 5 and 6 is disposed at substantially the level of the top face of tubular former 1. The rollers 5 and 6 are driven by a drive chain 7. A band or strip of fiberboard is fed between the rollers 5 and 6, to be scored along parallel longitudinal lines and is caused to move in the direction of arrow 8 over the top face of tubular former 1, but under a bending member 9. This member 9 has a U- shaped cross-section with its bight portion lying over the top face 10 of tubular former 1, being slightly spaced therefrom and parallel thereto and with the side legs extending longitudinally of the side faces of the tubular former and having a trailing portion substantially parallel to, and slightly spaced, from said side faces with an upstream portion which is flared or inclined away from the tubular former in the upstream direction. Thus, the fiberboard strip is caused to engage between the former member and the bending member and the latter will bend the strip along the two inner score lines made by the scoring rollers 5 and apply the band thus bent into an inverted U-shaped cross-section along the top and side faces of the tubular former member l. The side legs of the bent fiberboard strip are then engaged on each side of the tubular former member 1 by a pair of outer and inner co-acting pulling rollers 1 l and 12, the inner roller 12 extending through a slot 13 made in the side of the former member 1, as shown in FIG. 5; the outer roller 11 is covered with a coating of rubber 14 to increase friction. Each outer roller 11 is driven in rotation by a transverse drive shaft 15 extending above tubular member 1, driven by drive chain 7, and in turn connected to the outer rollers 11 by 45 helix gears 16 and meshing gears 17. The outer and inner pulling rollers l1, 12 are preferably slightly inclined with respect to the longitudinal axis of former 1, as shown in FIG. 2, to press the intermediate portion of the fiberboard strip down unto the top face 10 of former member 1.

Downstream from rollers 11 and 12, there is arranged on each side of former 1 an additional pair of outer and inner pulling rollers 18 and 19, similar to rollers 11, 12, and driven by .a transverse drive shaft 15, but arranged along axes perpendicular to the long axis of former member 1.

The inner rollers 12,19 are idle rollers rotatably mounted inside of tubular former 1, while the outer rollers- 11,18 are carried by brackets 20 (see FIG. 5) secured to longitudinally extending rods 21 disposed outwardly of and on each side of former member 1, said rods being secured to the side legs of an inverted U- shaped bracket 22 straddling the tubular former 1 and secured in position by tie bolts 23 secured to base 2.

A rod 24 is secured to the centre of bracket 22 and extends longitudinally above former member 1, its outer end being secured to the center of a second U- shaped bracket 25 straddling the downstream end of the tubular former 1 and spaced therefrom, said bracket being secured at its lower ends to the base 2.

Rod 24 serves to support the transverse drive shafts 15,15. Tie bolts 23 serve also to support the bending member 9.

Intermediate the pairs of rollers 11, 12, 18, 19, there are disposed bending rollers 26 in the form of pulleys, as shown in FIG. 4, with a peripheral groove having a V-shaped cross-section with a included angle and arranged for free rotation at the end of brackets 27 about axes inclined 45 with respect to the bottom and side faces of the former 1 and spaced from the lower corners of said former member 1, such that the fiberboard strip will engage between the rollers 26 along its outer score lines and the rollers will bend the marginal sections of the strip flat against the bottom face of the former member 1, whereby the longitudinal edges of the fiberboard strip will meet to form a joint substantially along the center of the bottom face of the former member, thereby completing a first tube which forms the inner layer of the eventual finished product.

It should be noted that the inner layer of the eventual finished product is bent around the former member, while being moved longitudinally of the same by the pulling rollers 11, 12, 18, 19. Then a second layer is applied to and bent around the first layer already moving along the former. For this purpose, a second strip of fiberboard is moved from a suitable supply in the direction of arrow 28 and passes between suitably spaced pairs of scoring rollers 29, similar to scoring rollers 5 and 6, so as to make longitudinal score lines corresponding to the four bending lines for the second layer.

The strip, indicated at 30, is then coated across its entire width with glue at its underface by gluing roller 31, supplied with glue from a known gluing mechanism 32; the glue-coated strip then travels around an idle roller 33 and then around a strip applying roller 34 with the glue-coated surface of the central longitudinal zone of the second fiberboard strip applied against the man ginal portions of the first strip overlying the bottom face of the former. Strip applying roller 34 is wider than member 1 and supports the whole width of the second fiberboard strip and is preferably driven by the drive chain 7. The side wings of the second strip are immediately engaged at their outer surface by bending rods 35, which are inclined towards the former member 1 along the sides thereof and inclined from the bottom towards the top of the former member, starting from the upstream to the downstream ends of said rods 35. The downstream ends of the rod 35 are fitted with collars 44 secured to rod supports 36 extending laterally longitudinally of former member 1 and spaced therefrom and secured at their downstream ends to bracket 25.

At the level of the downstream ends of bending rods 35, there are disposed bending rollers 37 opposite the two lower corners of the former member 1 and arranged at 45 angle and provided with V-shaped grooves, similar to bending rollers 26. These bending rollers 37 are each freely rotatably supported by a bracket 38, shown also in FIG. 3, which is secured to rod support 36 and which extends upwardly along the side of the former 1 to support another pair of bending rollers 39, similar to bending rollers 37 and 26, but arranged to coact with the upper corners of the former member 1 to bend the marginal portions of the second fiberboard strip back unto the top face of the former member 1 and thus unto the central portion of the first fiberboard layer moving along the former member 1. Thus, the longitudinal edges of the second strip form a joint along the center line of the former 1 at the top face thereof, said second strip joint being arranged out of register with the joint of the first fiberboard strip and preferably at exactly opposite sides of the finished tubular product. The second strip, being glue coated, will therefore adhere to the first strip along all the contacting surfaces thereof.

To positively apply the sides of the first strip to the sides of the second strip and to move the two strips in a positive manner along the former member 1, inclined pusher plates 40 and pairs of outer and inner pulling rollers 42,43 are arranged along the sides of the tubular former l. Pusher plates 40 are secured at the ends of members 41, in turn secured to collars 44, which serves to secure the bending rod 35 on the rod supports 36.

The outer and inner pulling rollers 42,43 have the same construction as the rollers 18,19 and are driven by a transverse shaft 45 through gearing 46,47, the shaft 45 in turn driven by the drive chain 7. If desired, the outer marginal portions of the second strip can be positively applied across their entire width to the central portion of the first layer by a positively driven roller across the top of the former member, but this is not shown as it is generally not necessary.

From the foregoing description, it is seen that the finished tubular product will consist of two overlying adhered layers of fiberboard with the joints of the meeting edges of each layer being out of register.

It is obvious that tubular products of fiberboard made of more than two layers can be produced by repeating the mechanism along the tubular former for applying, adhering and forming additional layers about the two first-named layers of fiberboard material.

Also, it is obvious that tubular products of other than square cross-sectional shape may be obtained by simply changing the polygonal Cross-sectional shape of the former member accordingly and by providing pulling rollers and bending rollers along the faces and corners respectively of the polygonal tubular former.

In order to seal the joint of the inner layer of fiberboard to provide a leak-proofjoint immediately at said inner layer, an endless flexible tape 50 is trained on wheels 51 and 52 near the upstream and downstream end of the tubular former 1 respectively and disposed within the tubular former member 1 for free rotation.

The tape 50 is preferably made of steel and its top run extends longitudinally within the tubular former member 1 while its bottom run, shown at 53, extends out of the bottom wall of the tubular former through suitable slits made therein and moves along the outside of the bottom face of said tubular member 1, as clearly shown in FIGS. 3 to 5. Thus, the marginal portions of the first fiberboard layer are applied against the moving bottom run 53 of the tape 50 by the bending rollers 26. However, the outside face of the tape 50 had been previously coated with glue by a gluing mechanism of conventional construction, indicated at 54, and supplying glue to a glue-coating roller 55 in rolling engagement with the bottom run of the steel strip opposite the upstream wheel 51. The latter is positively driven, for instance by a drive chain 55, engaging a sprocket 56 of wheel 51, chain 55 being in turn driven by drive chain 7 through suitable means not shown. The tape 50 will move at the same speed as the first layer of fiberboard and will seal the joint formed at the longitudinal edges of said first strip of fiberboard.

From the foregoing, it is apparent that the method of making tubular members from fiberboard strips is as follows.

The sheet of fiberboard material, in the form of continuous band or strip, is fed longitudinally to one end of a tubular former having a polygonal cross-section of the size and shape of the inside of the finished desired product. The method includes the steps of moving the strip along the former member while bending the strip to enclose and surround the faces of the former and such that the longitudinal outer portions of the strip will form a joint at the longitudinal edges of the strips.

The method further includes the step of adhering, by means of glue, another continuous flexible strip of fiberboard material with the central portion of said second strip applied on the face of the first strip provided with the joint. Thereafter, the method comprises the steps of bending the second strip around the first strip while moving the two strips along the former member, whereby the second strip is adhered to the first strip and forms a joint at its longitudinal edges, which is out of register with the joint of the first strip. Preferably, the method further includes means to seal the joint of the first strip to make the inner tubular member leakproof.

[ claim:

1. A machine for manufacturing tubular products of polygonal cross-section from strips of fiberboard of a width substantially equal to the perimeter of the finished products. said machine comprising an elongated former member of constant cross-sectional size and constant polygonal cross-sectional shape, means to support said former member in stationary position, means to supply a first one of said strips in transversely flat condition in a path longitudinally of, and close to, the exterior of said former member, means to move said first strip along said former member with the central longitudinal portion of said first strip applied against a first face of said former member, means to bend and to apply the remaining longitudinal portions of said first strip against the remaining faces of the said former member, as said first strip is being moved along said former member, so that the edges of said first strip are brought together to form a joint, whereby a first fiberboard tube is produced, means to supply a second one of said strip in transversely flat condition in a path longitudinally of, and close to, the exterior of said former member with the center line of said second strip substantially lying over the joint of said first tube, means to bend and to apply said second strip over the remaining faces of the tube formed by said first strip, so that the edges of said second sheet form ajoint along a zone of said first tube remote from said first-named joint and a second fiberboard tube is formed around said first tube, and means to apply glue to the contacting faces of one of said two tubes prior to the forming of said second tube around said first tube, said former member being of tubular construction and further ineluding means to seal the joint of said first tube, said last-named means comprising idle wheels mounted within said tubular former, an endless flexible tape trained on said wheels having one run extending inside said tubular former and the other run passing through slits of a wall of said tubular former and in sliding contact with the outside of said wall to move in register with the joint of said tube and at the speed of said first strip along said former member, and glue applying means coacting with a portion of said tape prior to the applying of said first strip unto said tape.

2. A machine as claimed in claim 1 wherein said former member is of square cross-sectional shape.

3. A machine as claimed in claim 1 further including means to score said sheets prior to their application unto said former member. 

1. A machine for manufacturing tubular products of polygonal cross-section from strips of fiberboard of a width substantially equal to the perimeter of the finished products, said machine comprising an elongated former member of constant cross-sectional size and constant polygonal cross-sectional shape, means to support said former member in stationary position, means to supply a first one of said strips in transversely flat condition in a path longitudinally of, and close to, the exterior of said former member, means to move said first strip along said former member with the central longitudinal portion of said first strip applied against a first face of said former member, means to bend and to apply the remaining longitudinal portions of said first strip against the remaining faces of the said former member, as said first strip is being moved along said former member, so that the edges of said first strip are brought together to form a joint, whereby a first fiberboard tube is produced, means to supply a second one of said strip in transversely flat condition in a path longitudinally of, and close to, the exterior of said former member with the center line of said second strip substantially lying over the joint of said first tube, means to bend and to apply said second strip over the remaining faces of the tube formeD by said first strip, so that the edges of said second sheet form a joint along a zone of said first tube remote from said first-named joint and a second fiberboard tube is formed around said first tube, and means to apply glue to the contacting faces of one of said two tubes prior to the forming of said second tube around said first tube, said former member being of tubular construction and further including means to seal the joint of said first tube, said last-named means comprising idle wheels mounted within said tubular former, an endless flexible tape trained on said wheels having one run extending inside said tubular former and the other run passing through slits of a wall of said tubular former and in sliding contact with the outside of said wall to move in register with the joint of said tube and at the speed of said first strip along said former member, and glue applying means coacting with a portion of said tape prior to the applying of said first strip unto said tape.
 2. A machine as claimed in claim 1 wherein said former member is of square cross-sectional shape.
 3. A machine as claimed in claim 1 further including means to score said sheets prior to their application unto said former member. 